Zobrazeno 1 - 10
of 58
pro vyhledávání: '"Helmut Hellwig"'
Autor:
Fouad G. Major, Helmut Hellwig
Publikováno v:
Physics Today. 51:83-84
Celestial and Mechanical Clocks.- Oscillations and Fourier Analysis.- Oscillators.- Quartz Clocks.- The Language of Electrons, Atoms, and Quanta.- Magnetic Resonance.- Corrections to Observed Atomic Resonance.- The Rubidium Clock.- The Classical Cesi
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::bf6ec5473d3da44d56a49a62cb39c503
https://doi.org/10.1063/1.882416
https://doi.org/10.1063/1.882416
Autor:
Helmut Hellwig
Publikováno v:
IEEE Transactions on Nuclear Science. 23:1629-1635
Today's precision oscillators and clocks are discussed. They include cesium standards, rubidium standards, hydrogen masers, and quartz crystal oscillators. A brief review of their basic design philosophy and performance characteristics is given. Bloc
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::2440fa0770a28f014e9d1af23b6680e4
https://doi.org/10.1109/tns.1976.4328553
https://doi.org/10.1109/tns.1976.4328553
Publikováno v:
IEEE Transactions on Instrumentation and Measurement. 27:349-354
HE RAMSEY TECHNIQUE [ 11 of separated oscillatT ing fields for atomic beam spectroscopy is widely used in atomic frequency standards, specifically in the cesium beam standard which forms the present basis for the definition of frequency and time inte
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::307f6c5c9b00fa9fba85df084189520a
https://doi.org/10.1109/tim.1978.4314710
https://doi.org/10.1109/tim.1978.4314710
Publikováno v:
Physics Today. 31:23-30
How many basic standards do we need? Standards are necessary to measurement, and for reasons of accuracy and convenience many measurements involve frequency. With atomic and molecular transitions serving as references, measurement precisions near 10
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::03efbf900955fb384e03bc60578e7c3b
https://doi.org/10.1063/1.2994867
https://doi.org/10.1063/1.2994867
Publikováno v:
Metrologia. 11:133-138
The accuracy of the rate or frequency of an atomic time scale is the degree to which its unit agrees with the SI second. Primary frequency standards are constructed in such a manner that they provide the most accurate possible physical realization of
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::9b7cbb40e61da437e6bd538884e1a807
https://doi.org/10.1088/0026-1394/11/3/006
https://doi.org/10.1088/0026-1394/11/3/006
Autor:
Helmut Hellwig
Publikováno v:
IETE Journal of Research. 27:362-365
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::8026c8d3ebe27bcad673e54edda9a24a
https://doi.org/10.1080/03772063.1981.11452488
https://doi.org/10.1080/03772063.1981.11452488
Autor:
Helmut Hellwig
Publikováno v:
Radio Science. 14:561-572
Today's time and frequency standards which are in active use ranging from the definition of the second to spacecraft applications are all based on atomic resonances in the microwave region controlling high-performance quartz crystal oscillators. The
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::3849c65f2b3a9c40cdd8aa78a9c9e2bd
https://doi.org/10.1029/rs014i004p00561
https://doi.org/10.1029/rs014i004p00561
Publikováno v:
IEEE Transactions on Instrumentation and Measurement. 28:122-132
We have investigated the feasibility of a special purpose frequency standard based on microwave absorption in ammonia gas (N15H3). Such a device would potentially fill a need in certain communications and navigation applications for an oscillator whi
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::93db34f0983aa2263ffe25f6711590cf
https://doi.org/10.1109/tim.1979.4314780
https://doi.org/10.1109/tim.1979.4314780
Publikováno v:
Metrologia. 13:17-28
The NBS primary frequency standard NBS-4 has been operating since January 1973. NBS-5 operated from January 1973 until March 1974. At this time NBS-5 was modified significantly and redesignated NBS-6. The extent and character of these design changes
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::f8938093e144accdfb104582a1f40bbf
https://doi.org/10.1088/0026-1394/13/1/005
https://doi.org/10.1088/0026-1394/13/1/005